Die rolling apparatus for knurling wire



DIE ROLLING APPARATUS FQR KNURLING WIRE Jack McShane, 'Rostraver Township, Westmoreland County, Pa.,"assighor to Pittsburgh Steel Gompany, a

corporation of Pennsylvania Filed Aug. 3., 1961, Ser. No. 129,103 4 iClaims. (Cl. 811-29) This invention relates to apparatus for knurling continuously moving wire in a die rolling operation.

It is desirable to provide wires that are to be used in reinforcing concrete, plaster and the like with rougherred surfaces to form a firm bond between the wires and the material in which they are embedded. The simplest way to do this is to kniirl the wires. In the past this has been done either by pulling a wire between kirurling rolls or driving'the rolls to feed the wires between them'j In both cases, the rolls have to be forced tightly against the wire by screw-downs or the like, and

the seeond case equipment obviously must be providcd fen driving the rolls. When idle rolls are used and. the wire is drawn between them, the knurl-forrning projections on the rolls. often are damaged either when the tension on thefwire. is. suddenly released, or when the machine is started in operation again after such a stop." A furtherfsource of damage to the rolls, are hard spots in the wire, such as where successive wires. are welded together. Anether shortcoming of existing knurling machines is thefrelatively low speed at which they must be operated, due to severe vibraft-ion and heating of theroll bearings,

It is among. the. objects of; this invention to provide wire knurling die rolling apparatus which requires no drivingequipment for the knurling rolls, which requires no screw-downs for pressing the rolls against the wire, which is very simple and inexpensive, which will not be damaged by sudden stopping or starting of the wire orbyhard. spots in it, and which can be operated satisfactorily at high speed.

In accordance, with this. invention the apparatus has a base, above which a pair of laterally spaced horizontal knurling.rolls are. disposed. They are located a short distance. apart to form a pass for a wire to be knurled. The rolls are pivotally mounted in the, inner ends of a pair of angularly disposed arms. that extend laterally away from each, other and forward in the direction of movement of the wire. Between the rolls and the outer ends or the arrns are means piv otally connecting the arms to the base on parallel axis aheadof the roll axes, so thata wire'that is being drawn forward between the rolls in engagement with them will pull the. rolls into dierolling engagement with it. Stops on the base limit rearward movement of the outer ends of the arms, while resilient meansalso mounted on, the base press the arms against the stops. With this arrangement, if a forwardly moving wire beingknurled, by the rolls suddenly exerts.

excessive pressure against thern, they can swing backward andftherebyrelieve the pressure.

Thef preferred embodiment of the invention is illustrated in the. accompanying drawing, in which FIG, 1 shows a wire being drawnthrough a die and the die rolling apparatus;

FIG. in an enlarged plan view of the die rolling apparatus;

FIG. 3 is. a frontview. thereof; and

FIG. 4 is an end view of the apparatus,

Referring to FIG. 1 of the drawing, a wire 1- from a payoff reel 2 extends around a block 3 and then may be reduced in diameter by drawing it through a. suitable die 4 by means of a driven take u'p reel 5. Between the die and the take-up reel, there is apparatus for die rollite tates arm:

3,077,131 Patented Feb. 12, 1963 ice ing the wire in order to form longitudinally spaced lgnurls along it. This apparatus, which is shown more clearly in the remaining figures of the drawing, has a base 7 that is pivoted at its back side on a central pivot pin 8 mounted in a suitable support (not shown). The base generally will be horizontal, although as far as the invention is concerned it could be in any other position. For the purpose of this description, it will be considered horizontal. Rigidly mounted in the base at two laterally spaced points is a pair of heavy pivot pins 9 which extend above the base. Pivotally mounted on each pin i an a m.

The two arms are inclined from the opposite ends of the base rearwardly across it and toward each other, but their inner ends are spaced apart. The inner end of each. arm is bifurcated to provide it with a horizontal slot 12, in which a horizontal roll 13 is disposed. The rolls are pivotally mounted on pins 14 extending vertically through the arms. Due to the oblique disposition of the arms, the axes of pins 14 are behind the axes of the pins 9 on which the arms pivot. The rolls are provided with circumferential grooves 16 forming a pass between the rolls for the wire 1. The base of each groove is provided with circumferentially spaced projections 17 of any desired shape, which will press into the wire to form longitudinally spaced depressions that define knurls 18 between them.

Mounted besides each arm 10, preferably behind its outer end, is an adjustable stop which may consistofa set screw 20 threaded in a boss 21 secured to the base. The front ends of the screws are engaged by the adjoining arms to limit rearward movement of the outer ends of the arms, whereby the distance that the rolls can be swung toward each other can be controlled to limit the depth of the knurls.

When it is desired to knurl a wire, the rolls are swung back manually far enough to permit the wire to be inserted between them, and either before or after this operation the front end of the wire is connected to the take-up reel 5. When that reel starts to pull the wire forward through the die and knurler, the friction of the wire against the rolls will swing them forward and toward each other until the outer ends of the arms tightly engage stop screws 2-0. As the wire continues to move forward between the rolls, it is rolled and knurled by them as shown, A tie bar 22 is mounted on the projecting upper ends of pins 9 to prevent the rolling pressure from springing them apart.

It will be seen thatno screw-downs are necessary for pressing the rolls against the wire, because the angle of arms 1 6 to the wire is such that the friction of the wire against the rolls willpull them into die rollingengagement with it. This simple butveryeffective idea materially reduces the cost and complexity of -the apparatus. Nothing new for pulling the wire throughthe rolls is necessary, because the same take-up reel that draws the wire through the drawing die can be used for drawing the Wire between the rolls. Pivot pin 8 allows the die rolling apparatus to swing laterally whatever distance is necessary for maintainingthewire straight between the front end ofthe die and the take-up reel.

Another feature of this invention is thatthe moment the wire breaks in front of the rolls-or stops, the longitudinal contraction due to release of tension onthe wire will swing the rolls backward slightly and thereby simultaneou sly causethem to move apart and release. their pressure. against the wire, This action prevents the wire from damaging theknurlson the rollseither at that i r wh n ha r rts m v n h d a n, h "same action occurs when hard spots in the wire pass between the rolls; that is, the rolls swing apart slightly to accommodate the hard spots so that the pressure against the rolls will not be raised excessively. However, it is neither desirable nor satisfactory to leave the outer ends of the arms entirely free to swing forward, because in such a case they would have to be pushed back manually until the wire grabbed the rolls, and because the inner end of one arm might attempt to swing away from the wire while the other arm is in engagement with its stop. That would prevent the rolls from engaging the wire as tightly as desired. Therefore, the outer ends of the arms are pressed strongly, but yieldingly, against the stops. One suitable way of doing this is to mount a set screw 25 in a boss 26 secured to the base in front of the outer end of each arm. Secured to the inner or rear end of each screw is a disc 27, from which a resilient member 28 extends back and into a recess 29 formed in the front of the arm behind the screw. The resilient member may be a strong spring or a cushion of rubber-like material. These cushions or the like normally strongly resist backward swinging of the rolls, but yet they are capable of being compressed enough to permit the foils to be swung backward slightly by the wire whenever necessary. The movement is just enough 'to prevent the rolls from being damaged.

One of the biggest advantages of this die rolling apparatus is that it can be operated at high speed, as high as the operating speed of available wire drawing appa- 'ratus. This makes it possible to knurl wire as it leaves the drawing die and at drawing speeds, instead of having to perform the knurling operation later at a much slower speed. There are at least two reasons why my apparatus can be operated much faster than those known hereto-fare, both being based on the same feature, which is the floating mounting of the rolls that permits them to swing away from each other when necessary. The result is that high wire speeds do not cause the machine to vibrate excessively, and the roll bearings run so cool that they do not even have to be water cooled.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

1 claim:

1. Die rolling apparatus for forming knurls on a longitudinally moving wire, said apparatus comprising a base having a back and a front, a pair of laterally spaced horizontal rolls provided with circumferentially spaced radial projections and disposed above the base a short distance apart to form a pass for a wire to be die rolled, a pair of angularly disposed arms each having an inner end pivotally supporting one of said rolls, the arms extending laterally away from each other and forward relative to the base, means between the rolls and the outer ends of the arms pivotally connecting the arms to the base on parallel axes ahead of the roll axes to permit a wire being drawn forward between the rolls in engagement therewith to pull them into die rolling engagement with it to form knurls thereon, stops on the base limiting backward movement of the outer ends of the arms, and resilient means mounted on the base pressing the arms against said stops, whereby increased pressure against the rolls by a forwardly moving wire being rolled by them can swing them backward and apart slightly to avoid damage.

2. Die rolling apparatus for forming knurls on a longitudinally moving wire, said apparatus comprising a base having a back and a front, a pair of laterally spaced 7O horizontal rolls provided with circumferentially spaced radial projections and disposed above the base a short distance apart to form a pass for a wire to be die rolled,

a pair of angularly disposed arms each having an inner end pivotally supporting one of said rolls, the arms extending laterally away from each other and forward relative to the base, parallel vertical pivot pins each extending through an arm between its roll and the outer end of the arm, the lower ends of the pins being secured to said base and the upper ends of the pins projecting above the arms, a tie bar connecting said upper ends, the pins being disposed with their axes ahead of the roll axes to permit a wire being drawn forward between the rolls in engagement therewith to pull them into die rolling engagement with it to form knurls thereon, stops on the base limiting backward movement of the outer ends of the arms, and resilient means mounted on the base pressing the arms against said stops, whereby increased pressure against the rolls by a forwardly moving wire being rolled by them can swing them backward and apart slightly to avoid damage.

3. Die rolling apparatus for forming knurls on a longitudinally moving wire, said apparatus comprising a base having a back and a front, a pair of laterally spaced horizontal rolls provided with circumferentially spaced radial projections and disposed above the base a short distance apart to form a pass for a wire to be die rolled, a pair of angularly disposed arms each having an inner end pivotally supporting one of said rolls, the arms extending laterally away from each other and forward relative to the base, means between the rolls and the outer ends of the arms pivotally connecting the arms to the base on parallel axes ahead of the roll axes to permit a wire being drawn forward between the rolls in engagement therewith to pull them into die rolling engagement with it to form knurls thereon, adjustable stops mounted on the base behind the outer ends of the arms to limit movement of the rolls toward each other, and resilient means mounted on the base in front of the outer ends of the arms and pressing them against said stops, whereby increased pressure against the rolls by a forwardly moving wire being rolled by them can swing them backward and apart slightly to avoid damage.

4. Die rolling apparatus for forming knurls on a longitudinally moving wire, said apparatus comprising a base having a back and a front, a pair of laterally spaced horizontal rolls provided with circumferentially spaced radial projections and disposed above the base a short distance apart to form a pass for a wire to be die rolled, a pair of angularly disposed arms each having an inner end pivotally supporting one of said rolls, the arms extending laterally away from each other and forward relative to the base, parallel vertical pivot pins each extending through an arm between its roll and the outer end of the arm, the lower ends of the pins being secured to said base and the upper ends of the pins projecting above the arms, a tie bar connecting said upper ends, the pins being disposed with their axes ahead of the roll axes to permit a wire being drawn forward between the rolls in engagement therewith to pull them into die rolling engagement with it to form knurls thereon, stops on the base limiting backward movement of the outer ends of the arms, resilient cushions engaging the front of the outer ends of the arms, and adjusting screws mounted on the base in front of the cushions, the screws having rear ends engaging the cushions and pressing them against the arms, whereby increased pressure against the rolls by a forwardly moving wire being rolled by them can swing them backward and apart slightly to avoid damage.

References Cited in the file of this patent UNITED STATES PATENTS 2,436,975 Ross Mar. 2, 1948 FOREIGN PATENTS 213,363 Austria Feb. 10, 1961 

1. DIE ROLLING APPARATUS FOR FORMING KNURLS ON A LONGITUDINALLY MOVING WIRE, SAID APPARATUS COMPRISING A BASE HAVING A BACK AND A FRONT, A PAIR OF LATERALLY SPACED HORIZONTAL ROLLS PROVIDED WITH CIRCUMFERENTIALLY SPACED RADIAL PROJECTIONS AND DISPOSED ABOVE THE BASE A SHORT DISTANCE APART TO FORM A PASS FOR A WIRE TO BE DIE ROLLED, A PAIR OF ANGULARLY DISPOSED ARMS EACH HAVING AN INNER END PIVOTALLY SUPPORTING ONE OF SAID ROLLS, THE ARMS EXTENDING LATERALLY AWAY FROM EACH OTHER AND FORWARD RELATIVE TO THE BASE, MEANS BETWEEN THE ROLLS AND THE OUTER ENDS OF THE ARMS PIVOTALLY CONNECTING THE ARMS TO THE BASE ON PARALLEL AXES AHEAD OF THE ROLL AXES TO PERMIT A WIRE BEING DRAWN FORWARD BETWEEN THE ROLLS IN ENGAGEMENT THEREWITH TO PULL THEM INTO DIE ROLLING ENGAGEMENT WITH IT TO FORM KNURLS THEREON, STOPS ON THE BASE LIMITING BACKWARD MOVEMENT OF THE OUTER ENDS OF THE ARMS, AND RESILIENT MEANS MOUNTED ON THE BASE PRESSING THE ARMS AGAINST SAID STOPS, WHEREBY INCREASED PRESSURE AGAINST THE ROLLS BY A FORWARDLY MOVING WIRE BEING ROLLED BY THEM CAN SWING THEM BACKWARD AND APART SLIGHTLY TO AVOID DAMAGE. 